It is difficult to support a woman in labour, especially in the second stage of labour, or if complications arise, when quickly obtaining support may be of primary importance. Various types of chairs and auxiliary devices are available for women in labour, but many difficulties are associated with their use and usually they are only suitable for use in a single labour position. The chairs and auxiliary devices are usually located in the room farther from the childbirth bed and cannot be safely used on the bed. It is also difficult to support someone in a wheelchair or a seat in a vehicle, if for some reason they cannot keep themselves in a normal sitting position. Support can be provided using a waist belt or a three-point belt like a seat belt, but it is difficult to form support that is both sufficiently supporting and at the same time flexible. If the support is sufficiently tight, it will limit movement and feel oppressive. On the other hand, support that is too loose will not necessarily prevent falling from the chair, or the person being supported from slumping, either due to his/her own movement, or the movement of the chair/seat. Particularly when being moved downhill in a wheelchair or child's pushchair, the person sitting will feel insecure without a support harness. Support harnesses are needed in the care of the elderly and invalids, as well as in general health care. The same problems of the relation between tightness and looseness also relate to supporting a woman in labour, but even more so, because in the second stage of labour large forces are used. It must be possible to remove the support, or alter it rapidly, and the woman in labour must also be able to detach herself from the support or harness, so that it will not feel oppressive. The support, for example a support harness, must also not squeeze or press on the woman uncomfortably at any stage.
For the reasons described above, support harnesses used especially in childbirth are difficult to implement satisfactorily.